Refresher Course: RC9 Environment. Radiation Protection of Environment under the Light of the New Concept of Radiation Protection of Non-Human Species

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1 Refresher Course: RC9 Environment Radiation Protection of Environment under the Light of the New Concept of Radiation Protection of Non-Human Species Summary Hansruedi Völkle Swiss Federal Office of Public Health, Environmental Radioactivity Section, c/o Physics Department, University of Fribourg Chemin du Musée 3, 1700 Fribourg, Switzerland The purpose of this presentation is to discuss the question of whether radiation protection should be extended to plants and animals. Until now the recommendations of ICRP have been focused exclusively on the protection of man from ionizing radiation. It was assumed that, if man is protected, the quality of the living environment is not impaired. In recent years adequate principles, recommendations and laws have become necessary in order to protect the environment from man made toxins. These recommendations aimed to conserve plants and animals, to maintain the diversity of species, the health and status of natural habitats and the natural resources of our planet, to warrant natural evolution and selection processes in order to transmit a healthy world to future generations. Reflections have been made as to whether particular protection of fauna and flora from ionizing radiation should be included. This article presents some considerations from the point of view of operational radiation protection and some comments to the work already done by ICRP committee 5. The final purpose is to invite the audience to make its own reflections and to communicate any criticisms, comments or suggestions to committee 5 of ICRP. Introduction Until today the recommendations of ICRP have been focused exclusively on the protection of man from ionizing radiation. It was assumed that, if man is protected, the quality of the living environment is not impaired. In recent years adequate principles, recommendations and laws have become necessary in order to protect the environment from man made toxins. These recommendations aimed to conserve plants and animals, to maintain the diversity of species, the health and status of natural habitats and the natural resources of our planet, to warrant natural evolution and selection processes in order to transmit a healthy world to future generations. Reflections have been made as to whether particular protection of fauna and flora from ionizing radiation should be included. New concepts have therefore been submitted for discussion which cover normal, existing and emergency situations. According to some scientists and working groups, although ionizing radiation is mostly a minor threat, it appears to be necessary to extend radiation protection of man to plants and animals. A holistic view concerning environmental protection including all potential anthropogenic hazards should also be applied. Today environmental protection communities no longer take it for granted that, as long as man is protected from ionizing radiation, the fauna and flora are also adequately protected in all cases. ICRP has therefore formed a Task Group and now also a new committee (Committee 5 on Protection of the Environment, chairman Professor Jan Pentreath) that has produced ICRP Report Nr. 91 [3] and two draft papers entitled Protection of Non-human Species from Ionizing Radiation [1] and "The Concept and Use of Reference Animals and page 1 from 13

2 Plants for the purpose of Environmental Protection" [2]. In order to stimulate a broad discussion of these issues, these draft reports have been published by ICRP on Internet. This article presents some considerations from the point of view of operational radiation protection, whether or not special protection of the living environment is needed, without making any claim with respect to its comprehensiveness, and some suggestions for starting points for operational implementations. Finally a short overview will be presented on work in progress or already done in this field by Committee 5 of ICRP. These reflections are at the moment only in draft version and not yet approved by the main commission of ICRP. The purpose of this lecture is therefore to invite the audience to make its own reflections and to communicate any criticisms, comments or suggestions to committee 5 of ICRP. 1. The protection of man from ionizing radiation (Basic principles) Soon after man had started developing and testing nuclear weapons, employing nuclear power to produce energy, and applying radioisotopes and ionizing radiation in medicine, industry and research, the radiation protection community became aware of the fact that these applications did not only provide advantages but also involved risks for humans. By the end of the 1920 s, H. J. Muller realized that ionizing radiation could cause the mutation of genes on drosophila flies. At about the same time it does become obvious that radiation could induce cancer by mutation of the DNA in the cell nucleus. Founded in 1928, ICRP (The International Commission of Radiological Protection) initially concentrated on the protection of man from the effects of ionizing radiation. In order to safeguard human health ICRP recommends the following goals: to avoid deterministic effects, to limit stochastic effects in single individuals, to minimize stochastic effects in populations. With this concept, mankind, both as a whole and an individual was thought to be adequately protected. Deterministic effects, i.e., health detriments to organs or tissues, are caused by cell necrosis due to irradiation. The severity of the health detriment increases with dose and, as is currently commonly accepted, starts at some dose threshold. Stochastic effects, i.e., cancer, leukemia, or genetic defects, are caused by DNA mutations of irradiated but surviving cells in particular misrepaired DNA double strand breaks. While the probability of developing a health detriment increases (probably) linearly with dose, the severity of the detriment does not. According to the LNT hypothesis (Linear no Threshold Hypothesis) based on present knowledge, there does not exist a dose threshold for stochastic effects. 2. The protection of the living environment (Needs and basic principles) Let us start by a citation from the Bible (Genesis, Chapter 1), where man is entrusted by God with the responsibility over the living environment: 26: Then God said: "Let us make man in our image, after our likeness. Let them have dominion over the fish of the sea, the birds of the air, and the cattle, and over all the wild animals and all the creatures that crawl on the ground." 27: God created man in his image; in the divine image he created him; male and female he created them. page 2 from 13

3 28: God blessed them, saying: "Be fertile and multiply; fill the earth and subdue it. Have dominion over the fish of the sea, the birds of the air, and all the living things that move on the earth." 29: God also said: "See, I give you every seed-bearing plant all over the earth and every tree that has seed-bearing fruit on it to be your food; 30: and to all the animals of the land, all the birds of the air, and all the living creatures that crawl on the ground, I give all the green plants for food." At the beginning of the industrialized era man has become less threatened by the environment but now he poses more of a threat to the environment instead. He does so by, 1) Exploiting natural resources and sources of energy; 2) Excessively burdening the environment with man-made toxins and bio-active substances; 3) Changing natural processes and equilibria and so disturbing natural evolution and selection processes; 4) Furthermore by selection, crossing, rearing and hybridization of plants and animals he has produced species optimized for his own purposes and without concern for adapting to environmental conditions in the best way as is the case for natural evolution; 5) And finally, he brought species to regions and habitats where they are not indigenous and thus modified the natural equilibrium between species. The so called bioinvasion, done on purpose or by negligence, leads to mono-cultures and consequently the disappearance rate for species is today the highest in the 4.6 billion years that the earth has existed. In order to preserve nature for future generations, protection of the living environment therefore is beginning to gain in relevance. This results in the necessity for countermeasures to safeguard the environment in a manner which will enable future generations to continue to inhabit our planet. These measures are to ensure not only: 1) the preservation of species, but also 2) the biological diversity of plants and animals, 3) their natural habitats, and 4) the equilibria between species. The aim is to obtain that natural selection and evolution processes are able to function unimpeded by man. Organizations, bodies, governments and individuals alarmed by the above mentioned evolution have drawn up recommendations, measures and laws in order to protect the living environment, to maintain biodiversity and the natural habitats for the different species and to avoid disturbance of natural evolution and selection processes. So let us continue with some citations in the context of animal and environmental protection: The World Charter for Nature established by the UN General Assembly in October 1982 states: "Every form of life is unique, warranting respect regardless of its worth to man, and to accord other organisms such recognition man must be guided by a moral code of action.... Nature shall be respected and its essential processes shall not be disrupted". page 3 from 13

4 The Swiss Federal Act on Animal Protection, Article 2: Principles, says: 1. Animals shall be treated in the manner which best complies with their needs. 2. Anyone who is concerned with animals shall, in so far as circumstances permit, safeguard their welfare. 3. No one shall unjustifiably expose animals to pain, suffering, physical injury or fear. As further example, the Animal Care and Protection Act of Queensland, Chapter 1, Part 2, Division 1: Purposes of Act, states: The purposes of this Act are to do the following a) promote the responsible care and use of animals; b) provide standards for the care and use of animals that (i) achieve a reasonable balance between the welfare of animals and the interests of persons whose livelihood is dependent on animals; and (ii) allow for the effect of advancements in scientific knowledge about animal biology and changes in community expectations about practices involving animals; c) protect animals from unjustifiable, unnecessary or unreasonable pain; d) ensure the use of animals for scientific purposes is accountable, open and responsible. Further, The Convention on the Conservation of European Wildlife and Natural Habitats (Preamble to the Bern Convention) contains the sentence: "... wild flora and fauna constitute a natural heritage of aesthetic, scientific, cultural, recreational, economic and intrinsic value that needs to be preserved and handed on to future generations..." The European Union Council's Directive on the conservation of natural habitats and of wild fauna and flora states: Member States must take all necessary measures to guarantee the conservation of habitats in special areas of conservation, and to avoid their deterioration. The Directive provides for cofinancing of conservation measures by the Community. Member States must also: encourage the management of features of the landscape which are essential for the migration, dispersal and genetic exchange of wild species; establish systems of strict protection for those animal and plant species which are particularly threatened (Annex IV) and study the desirability of reintroducing those species in their territory; prohibit the use of non-selective methods of taking, capturing or killing certain animal and plant species (Annex V). The Member States and the Commission must encourage research and scientific work that can contribute to the objectives of the Directive. And finally, The Rio de Janeiro Convention on biological diversity contains the statement: page 4 from 13

5 States are responsible for the conservation of their biological diversity and the sustainable use of their biological resources. 3. Do we need to protect fauna and flora from ionizing radiation? For a long time the explicit protection against ionizing radiation of the living environment was not an issue. So ICRP in its Publication 60 states that man is the most sensitive species and therefore should be primarily protected. As long as protection of man is adequate, it is deemed that the living environment is also sufficiently protected. So additional measures to protect the living environment seemed not to be necessary. In the past protection of the fauna and flora became more and more a necessity, and not only for the survival of mankind. This statement was therefore questioned and situations have been identified where man has sufficient protection but not the living environment. So it became necessary to identify situations where additional protection is required and what the goals of these measures are and how they should be put into practice. This leads to the abandonment of the past practiced anthropo-centric view in favor of a bio-centrical or eco-centrical one which would include all potential hazards to plants and animals. Should it be necessary to provide risk assessments for fauna and flora, then this would not be limited to risks due to ionizing radiation, but would also include all hazards associated with other environmental toxins and bioactive substances. ICRP has recognized this issue and has organized a Task Group and named a committee 5 (Protection of the Environment) with the task of establishing first reflections and recommendations on this issue. 4. How does the protection of man from ionizing radiation differ from that of the living environment? Primarily, the main difference in the protection of man is that for the living environment the protection of single individuals is not a major concern. However, the following situations are to be avoided: increase of morbidity in plant and animal species (i.e., inhibition of growth, or increase of susceptibility to pests or toxins), acceleration of mortality (e.g., reduction of the natural life span), reduction of the capacity to reproduce (i.e., reduction of competitiveness to other species), or detectable changes of the DNA of single individuals, irrespective of whether they arise from stochastic or non-stochastic dose effect relationship. Secondly, avoidance of stochastic effects does not seem to be a major concern. More important is that genetic and biological fitness of species should not be adversely affected. This includes their general health, their diversity, their natural habitat, and the equilibrium between species. Numerous questions now remain to be answered. Is it sufficient to act only once any of the above symptoms have been detected, i.e., when the species might not yet be endangered, but their biological and genetic fitness is already affected? Is the only reason for protection of the living environment to ensure long-term survival of man, or are there other moral or ethical considerations which need to be taken into consideration (e.g., animal rights aspects)? And one of the most prevalent questions which still requires an answer is whether we can stop at the protection of the living environment, i.e. biota, or do we also have to include the non-living environment, i.e. abiota? page 5 from 13

6 Even though all these aspects seem to be readily comprehensible, it still needs to be checked how they can be operationally implemented. To ensure world-wide operational compliance, and not just in the industrialized world, and to avoid a significant north-south discrepancy, it seems reasonable to opt for a pragmatic solution by establishing a simple framework of recommendations. However, difficulties will possibly arise from the fact that the only planned applications are those termed Practices by ICRP. Only radionuclide emissions can be controlled in these particular situations in such a way that the protection goals will not only include man but also the living environment. On the other hand for actions termed Interventions by ICRP, we only do have protection measures for man (e.g., measures at the work place, evacuation or relocation, measures and limitations for food distribution, etc.). However, such measures do not exist for the living environment. This can easily be exemplified by the Chernobyl exclusion zone: it is not possible to define measures to retroactively protect fauna and flora from radiation due to the Chernobyl accident. It is therefore more sensible to limit the scope of protection of the living environment to Practices, at least at the beginning. Moreover, it seems reasonable for the protection of the living environment to use a concept of "soft" Derived Consideration Levels instead of Dose Limits or Dose Constraints as in use for human radiation protection. 5. What situations need particular attention in radiation protection of fauna and flora? The above-mentioned ICRP 60 statement that protection of man also sufficiently protects the living environment in many cases is still true. Possible exceptions can occur under circumstances where the human population is removed from the exposure area, that is by evacuation or relocation, or when no human habitats are directly affected. In these cases, radionuclides could cause exposure of animals or plants without human exposure. A few examples of such circumstances include: areas used for nuclear weapon testing, radionuclide emission areas in aquatic or marine environments, restricted areas such as for example the 30-km exclusion zone at Chernobyl, or the immediate environment of underground radiological or nuclear waste depositories. It therefore appears to be reasonable to concentrate on these exceptional circumstances for considerations concerning radiation protection of fauna and flora. 6. Possible stages to operational implementation If special protection from ionizing radiation for the living environment is necessary, the following points have to be taken into account: 1. The circumstances under which separate protection of fauna and flora is warranted are to be identified. These are any circumstances under which protection of man does not automatically ensure sufficient protection for animals and plants. 2. The recommendations which are to be defined in this regard should be sufficiently pragmatic to be readily operational. Protection of fauna and flora should be limited to Practices in the sense defined by ICRP, i.e., to planned use, applications or emissions of page 6 from 13

7 radioactive material as only these can be controlled by appropriate measures. Protection measures in the case of Interventions should still be limited to the protection of man. 3. Protection goals are to be defined for fauna and flora, i.e., any detriments that are to be avoided or limited. Here, a holistic point of view, considering all possible hazards or detriments also including non-radiological risks, appears to be the most sensible approach. This necessitates multi-disciplinary cooperation between radiation protection, ecology, biology and zoology. 4. Only a limited number of reference animals and plants are to be selected. The necessity of extending this concept from reference species to critical groups of plants, animals and endangered species should be discussed. 5. A simple dosimetry system for the reference populations has to be developed. It should be based on a kind of Dose Equivalent for Fauna and Flora (DEFF i ) as proposed by the ICRP Task Group (see chap. 7.4), which is to be defined in analogy to the effective dose in man E and should encompass dose limits for the dose quantity DEFF i, expressed as a multiplicative factor of the natural radiation background of the species which are taken into account. The lowest limit for DEFF i should not be chosen below a factor of 10 of the natural background exposure of that species. Additional research on the eventual stochastic effects of radiation on animals and plants is necessary. 6. In addition to the already existing national laws and regulations which are based on E, analogous "soft" Derived Consideration Levels for radionuclide concentrations in air, water, etc., are to be established for the exceptional conditions specified in Chapter 5. These derived quantities are to be based on DEFF i. Appropriate monitoring programs should ensure compliance with the sets of Derived Consideration Levels. 7. It is also to be ensured that improved protection of fauna and flora, i.e., the non-human environment, is achieved, and that this does not result in an increased risk or in increased detriments from ionizing radiation for man, i.e., the human species. 7. How to put this into practice: Work in Progress at ICRP Committee 5 In the following we present some of the ideas proposed by ICRP Committee 5 on Protection of the environment, contained in the draft "The Concept and Use of Reference Animals and Plants for the purpose of Environmental Protection" [2] and in ICRP Report 91 [3] Concept and choice of reference animals and plants Analogous to critical groups in radiation protection of man (i.e., groups of people most exposed or most at risk), the definition of critical populations for fauna and flora would be the most sensible approach. A more practical way is suggested by ICRP Committee 5 Draft in choosing reference populations for the four most important groups of life: land animals (including birds) shelf animals aquatic animals plants page 7 from 13

8 in order to cover the 3 main environments: terrestrial freshwater Marine ICRP Committee 5 has proposed a set of 9 reference animals in their draft: Deer Rat Duck Frog Trout Flat fish Bee Crab Earthworm and 3 reference plants: Pine tree Grass Seaweed The key criteria for their selection are: Legislation to wildlife protection Use in toxicology testing Human resource Data on radionuclide accumulation Data on radiation effects Amendable to further study Public resonance Nevertheless, specific groups and species perhaps need particular attention, for example: plant or animal species which are most at risk in certain exposed situations or in a specific radiation or radioactivity environment, species which have been shown to be less robust under other anthropogenic environmental stressors, or which are already weakened by other chemical or bioactive toxins, species at risk of extinction, and species inhabiting specific habitats (niches) in the environment and which are therefore especially vulnerable to changes in their habitat Radiation dosimetry for animals and plants To estimate internal and external radiation doses in animals and plants different dosimetric models have been studied. It seems that solid spheres or cylinders or solid ellipsoid models are the most suitable and the most pragmatic ones. For gamma emitters and for beta emitters the fraction of the primary energy (F E ) absorbed within the target is calculated by Monte page 8 from 13

9 Carlo methods. For alpha particles the range in tissues is small, and so it is assumed that all the alpha energy is absorbed within the target. This leads to a set of dose (rate) per unit concentration factors as well as for external and for internal exposure, the latter normally assumed to be uniformly distributed within the target. However, the possible effects of inhomogeneous radionuclide distribution within the target need further studies The effects of radiation on animals and plants Energy deposited along the track of ionizing radiation within living tissues causes damage at the cell and sub-cell levels mainly by single and double strand breaks of the DNA molecules. The frequency and clustered damages depend upon the linear energy transfer LET, i.e. the energy per length of particle track. Whilst single strand breaks are repaired error-free in most cases there is a certain probability of misrepair in double strand breaks. Based on available data on chronic effects of radiation on animals and plants FASSET (Framework for assessment of environmental impact) has developed a Radiation Effects Database (FRED). Also the data show great variation, we will cite some examples from the Draft of ICRP committee 5. For mammals effects to early mortality, mutation, and reduced reproductive success have been recorded in dose ranges from 0.1 to 1 mgy/h; for other vertebrates the available data are poorer, but there are data for some marine species. For plants detrimental effects have been observed in pine trees at dose rates to the order of 2.4 mgy per day and for deciduous trees at doses 2 to 10 times higher. Conifers are considered to die at dose rates of 120 to 240 mgy per day. According to FASSET the threshold for statistically significant effects in most studies is about 100 μgy/h whilst the critical dose rate in μgy/h from a Canadian Proposal for Discussion is slightly lower: 11 for mammals, 57 for birds, 11 for amphibians and reptiles 114 for benthic invertebrates and 571 for fish. The expected non-effect dose rate is 10% of these values for each species. From the Conclusions of IAEA Technical Report Nr. 332 (1992) we cite that: "It is highly probable that limitation of the exposure of the most exposed humans (the critical human group), living on and receiving full sustenance from the local area, to 1 msv per year will lead to dose rates to plants and animals in the same area of less than 40 μgy/h." and "...there is no convincing evidence from the scientific literature that chronic radiation dose rates below 40 μgy/h will harm animal or plant population" Definitions, terms, quantities and units At present there is no consensus whether LET and RBE factors used for human radiation protection can be applied in the same way for animals and plants. Nevertheless, RBE phenomenon also exists in animals [14]. So, as deterministic effects are considered of great importance, UNSCEAR suggested a weighting factor of 5 for alpha particles in all living things other than man. Some authors propose the use of a dose equivalent for fauna and flora (DEFF) obtained from the absorbed dose [Gy] multiplied by a qualifying factor analogous to the w R factor for humans. This factor could be called eco-dosimetry weighting factor e R, with values of 1 and 20 respectively for beta/gamma and alpha radiation and calculated from LET for radiation in water (as for humans). Although discussion about this issue is not closed it seems sure that the absorbed dose remains the key quantity for exposure assessment of plants page 9 from 13

10 and animals. It seems useful to record dose information separately for the high and the low LET fraction Assessing effects in terms of Derived Consideration Levels In its draft Committee 5 suggests comparing additional doses to plants and animals with the natural exposure of the same species under normal conditions. As long as additional doses are only a fraction of the natural ones they will not produce any significant concern. Observable radiation effects on plants and animals seem to be primarily of non-stochastic nature. For low doses, as DNA in animals and plants are similar to those in humans, the LNT hypothesis used for humans could be taken as a basis. As natural radiation is a reference for the normal and typical exposure of fauna and flora, the derived information for each type of plant and animal could be expressed simply - in terms of multiples of background radiation, together with - size and area affected, - fraction of population exposed and the - actual animals and plants concerned. This is certainly an advantage in the face of the effects of chemicals where the levels required to produce a given effect are many orders of magnitude greater than those expected in the majority of environmental situations [14]. On this basis Derived Consideration Levels for radionuclides in the environment would be calculated serving as a basis for any further action in a real case. So, according to ICRP [3] a logarithmic scale seems appropriate for the assessment of relative radiation doses to plants and animals, with: - Level 1 < background - Level 2 = background range - Level 3 or higher > 10 times background Only for Level 3 or higher actions have to be considered according to ICRP [3] depending upon nature of effects, number and type of individuals affected, spatial and temporal aspects, etc. A remedy may be considered at extremely high relative doses, and this may apply also to "Interventions". From the draft report of ICRP Committee 5 (and from other sources) we cite as examples some values of natural background radiation level for some species: For aquatic animals between 1 to 2 and 10 to 14 μgy per day, for the freshwater environment some 0.5 to 18 μgy per day. For the terrestrial environment the following values have been published: 0.8 to 2 μgy per day for earth worm, 0.6 for deer, 0.8 for mice, 0.7 for fox and 0.2 μgy per day for cattle. For pine tree doses in the range of 2 to 25 mgy per day can have effects of reduced trunk growth and morphological alterations in pine needles Creating a Reference Set The set of Reference Animals and Plants proposed by the Draft of ICRP Committee 5 will be completed by: extended biological description for each of the twelve types, page 10 from 13

11 dimensions for the dose models (i.e. axes of the ellipsoid), values for dose per unit concentration (μgy/day per Bq/kg) for external and internal exposures for the principal naturally occurring radionuclides as well as for the principal artificial radionuclides, reference internal and external naturally-occurring radionuclide concentrations (Bq/kg), the latter for seawater, fresh water and soil, reference background dose rates (μgy/day) for each type in order to create a set of Derived Consideration Levels, guideline transfer factors (for the terrestrial environment) and concentration factors (for the aquatic environment) for a set of artificial radionuclides, a set of information summarizing the actual knowledge about the effects of radiation on the type of animal and plant considered and for different stages of the life cycle of each type. According to ICRP [3] the next steps would be: - to reach an international consensus among all the concerned groups and bodies, - to get this concept widely accepted, - to compile all relevant data on the protection of fauna and flora, - to choose the terminology, - to define the relevant quantities in order to develop a workable framework, - this should be done in cooperation with bodies not involved in radiation protection and, to avoid duplication, a "division of responsibility" between ICRP, UNSCEAR and IAEA should be set up [3]. 8. Conclusions There is without doubt a need for action to protect the living environment in order to maintain biodiversity and the natural habitats for the different species as well as to avoid disturbance of natural evolution and selection processes. Discussion is necessary as to whether this also concerns the exposure of plants and animals to ionizing radiation. If this is so, the work already done by ICRP Committee 5 and other groups (see chap. 9) will be extremely helpful in attaining this goal. Moreover, the suggestions for their practical implementation which are contained in the Drafts published by Committee 5 of ICRP (see [1], [2] and [3]) seem to be the best way to achieve this. It is, however, most important that a consensus be obtained on these questions between all the bodies involved, such as governments, authorities, scientists etc. and this before further actions are taken or recommendations are issued. However, to obtain a framework of rules and recommendations that will be accepted by all actors in this field and that can be easily put into practice in the near future, one has to be pragmatic and to concentrate essentially on those special situations where protection of man does not automatically include that of the living environment. In all situations where man is present and therefore concerned by radioactivity released to the environment he remains the most sensitive species and his protection from ionizing radiation will ensure, that biota is sufficiently protected. Furthermore this concerns the protection of species and not individuals, as in the case of human radiation protection. It has to be taken into account that the effects of radiation on plants and animals are mainly of non-stochastic nature, notwithstanding that ionizing radiation is a minor threat most of the time. The concept of reference animals and plants, the definition of Derived Concentration Levels based on absorbed doses in plants and animals as multiples of the natural exposure (in a logarithmic scale) of these species seems page 11 from 13

12 reasonable. Actions must only be considered for irradiation higher than 10 times natural background levels. The Derived Concentration Levels should be considered only as soft levels. They should primarily trigger further investigations or actions. Finally, it seems appropriate to concentrate more on "Practices" than on "Interventions". We hope that this presentation will stimulate a broad discussion on this issue among all concerned bodies and scientists. 9. Some References For further information see the following (not exhaustive) list with ICRP publications and Drafts and further recent publications to this issue: [1] ICRP Draft for Discussion 02/305/02: Protection of Non-Human Species from Ionizing Radiation. (Draft , not yet approved by the Commission). [2] ICRP Draft for Discussion 02/72/05: The Concept and Use of Reference Animals and Plants for the purpose of Environmental Protection. ICRP 02/72/05 (Draft , not yet approved by the Commission). [3] ICRP Publication Nr. 91: A Framework for Assessing the Impact of Ionizing Radiation on Non-Human Species; Vol. 33, No. 3, 2003, Pergamon [4] IAEA TECDOC-1270: Ethical consideration in protecting the environment from the effects of ionizing radiation. A report for discussion. IAEA, Vienna, February [5] IAEA Conference & Symposium Papers 17/P: Protection of the Environment from ionizing Radiation. Proceeding of the Third International Symposium on the Protection of the Environment form Ionizing Radiation (SPEIR 3) held in Darwin, Australia, July 2002, ISBN , UN Vienna [6] UNSCEAR (Draft): Effects of ionizing radiation on non-human biota. Fifty-third session, UNSCEAR Vienna, 26 to 30 September 2005, Draft Version [7] UNSCEAR (Draft): Methodologies for the assessment of exposure to biota from radionuclides discharged to the environment, UNSCEAR Vienna, 26 to 30 September 2005, Draft Version [8] Radiological Protection of the Environment: Summary Report of the Issues. NEA- OECD, 2003, Paris [9] R. J. Pentreath: A System for radiological protection of the environment: Some initial thoughts and ideas. J. Radiol. Prot (19/2), pp [10] R. J. Pentreath and D. S. Woodhead: A System for Environmental Protection: Reference Dose Models for Fauna and Flora. Proceedings of IRPA-10 Congress, May 14 to 19, 2000, Hiroshima. [11] R. J. Pentreath: Radiation Protection of People and the Environment: Developing a common Approach. J. Radiol. Prot (22), pp [12] Alfred Hefner and Hansruedi Völkle: Brauchen wir einen Strahlenschutz für die lebende Umwelt? StrahlenschutzPRAXIS 4/2003, pp [13] Lars-Erik Holm: ICRP and Radiation Protection of Nun-Human Species. Proceedings of IRPA-11 Congress, April 23 to 28, 2004, Madrid. [14] S. J. Birkinshaw, M. C. Thorne and P. L. Younger: Reference biospheres for postclosure performance assessment: Inter-Comparison of SHETRAN simulation and BIOMASS results. J. Radiol. Prot (25), pp [15] Journal of Radiological Protection, Vol. 24, Number 4A, December 2004: Special Issue: Framework for assessment of environmental impact (FASSET) of ionizing radiation in European ecosystems (10 papers). page 12 from 13

13 [16] C.-M. Larsson: Regulation and decision-making in environmental radiation protection. Radioprotection, Suppl. 1, Vol. 40 (2005), pp. S905-S911. [17] R. J. Pentreath: Dosimetric considerations with respect to Reference Animals and Plants. Proceedings of the Seventh Internal Symposium of the Society for Radiological Protection (2005), pp [18] R. J. Pentreath: Ethics, genetics and dynamics: an emerging systematic approach to radiation protection of the environment. Journal of Environmental Radioactivity, Vol. 74 (2004), pp See also: FASSET: Framework for assessment of environmental impact: or: The International Union of Radioecology: page 13 from 13